First, I lather myself in oil, crisco usually. Then I dim the lights until its barely a flicker. I tried candles once, but the fire department won't do house calls for me anymore and the city threatened to sue if it happened again. Next, I insert the enema. This next bit is a bit messy so I'll just skip to the cleanup. So, after I finish re-coiling the garden hose and the drywall stains have set, I'm usually good to go. I stop to take a smoke, putting the butt out on my chest (which is where the crisco comes into play) and by then I have an idea of a good plot, subplot, characters, and scene.
On a serious side, never understood rituals. Seemed like they were just one extra step of procrastination. To each their own, if they work for you... but a simple shut of the door is all I need. And the enema. But that's another story.